SpringBoot Cannot construct instance of org.springframework.boot.actuate.health.Health (no Creators, like default construct, exist): no default no-arguments constructor found

        springBootVersion = '2.1.1.RELEASE'
        springCloudVersion = 'Greenwich.RC2'

Using org.springframework.boot.actuate.health.Health as DTO:

@FeignClient("foo-service")
public interface FooClient {

    @GetMapping(path = "actuator/health", produces = MediaType.APPLICATION_JSON_VALUE)
    @ResponseBody
    Health health();
}

leads to this error:

feign.codec.DecodeException: Type definition error: [simple type, class org.springframework.boot.actuate.health.Health]; nested exception is com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of `org.springframework.boot.actuate.health.Health` (no Creators, like default construct, exist): no default no-arguments constructor found
 at [Source: (PushbackInputStream); line: 2, column: 3]
    at feign.SynchronousMethodHandler.decode(SynchronousMethodHandler.java:180) ~[feign-core-10.1.0.jar:na]
    at feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:140) ~[feign-core-10.1.0.jar:na]
    at feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:78) ~[feign-core-10.1.0.jar:na]
    at feign.ReflectiveFeign$FeignInvocationHandler.invoke(ReflectiveFeign.java:103) ~[feign-core-10.1.0.jar:na]
    at com.sun.proxy.$Proxy144.health(Unknown Source) ~[na:na]

Comment From: snicoll

Feign usage is not handled in this project so please do not report an issue against it here. Health is not a DTO and is not supposed to be used as such. If you have more questions, please ask on StackOverflow: as mentioned in the guidelines for contributing, we prefer to use GitHub issues only for bugs and enhancements.

Comment From: octopus-prime

Health is not a DTO and is not supposed to be used as such.

@JsonInclude(Include.NON_EMPTY)
public final class Health {

    private final Status status;

    private final Map<String, Object> details;

    /**
     * Create a new {@link Health} instance with the specified status and details.
     * @param builder the Builder to use
     */
    private Health(Builder builder) {
        Assert.notNull(builder, "Builder must not be null");
        this.status = builder.status;
        this.details = Collections.unmodifiableMap(builder.details);
    }

    /**
     * Return the status of the health.
     * @return the status (never {@code null})
     */
    @JsonUnwrapped
    public Status getStatus() {
        return this.status;
    }

Note the JSON annotaions! May be it's a DTO and produces JSON like

{
    "status": "DOWN"
}

when calling the actuator health endpoint?!

Comment From: octopus-prime

Workaround because org.springframework.boot.actuate.health.Health is not reusable:

@Data
public class Health {

    private Status status;
}

But the own Health class is not usable in e.g. HealthAggregator.

Comment From: TehBakker

Was surprised to have the same issue when fetching from RestTemplate with jackson.

org.springframework.http.converter.HttpMessageConversionException: Type definition error: [simple type, class org.springframework.boot.actuate.health.Health]; nested exception is com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance oforg.springframework.boot.actuate.health.Health(no Creators, like default construct, exist): no default no-arguments constructor found Feels weird to have to go through a homemade bean to be able to fetch subsystems health in tbheir HealthIndicator no?

Comment From: wilkinsona

@TehBakker As @snicoll said above, Health isn't intended to be used as a client-side DTO.